Dozens of international relief flights and supply shipments sped on their way, transporting everything from skilled rescue workers to water purification tablets. The United States said it was sending tons of medical supplies in a military airlift, as well as rescue squads and medical teams.

Most rescue workers were flying here to Kerman, to make their way by land to Bam, 120 miles to the southeast.

Iradj Sharifi, rector of the faculty of medicine in Kerman, said that in the pre-dawn earthquake, ''Five thousand people were killed on the spot and there are 20,000 people under the rubble.''

Brigadier Mohammadi, commander of the army in southeastern Iran, told state television, ''We need help -- otherwise we will be pulling corpses, not the injured, out of the rubble.''

There were grim but uncertain predictions that the death toll -- in a 2,000-year-old city of 80,000 people -- might keep growing.

''As more bodies are pulled out, we fear that the death toll may reach as high as 40,000,'' said Akbar Alavi, the governor of Kerman, the provincial capital, according to The Associated Press. ''An unbelievable human disaster has occurred.''

The earthquake, which Iranian agencies measured at 6.3 and American agencies at 6.7, rocked Bam, 610 miles southeast of the capital, Tehran, at 5:28 a.m. Friday.

Government spokesmen said that foreign aid workers would not need entry visas and that aid would be welcome from everywhere but Israel. In a televised address, President Mohammad Khatami urged on rescue efforts, thanked the nations that were sending aid and said he was preparing to leave for Bam.

Volunteer rescue workers from around the country hurried into the city, some equipped with shovels, some joining survivors in clawing through the rubble barehanded. About 7,000 police officers were sent to Bam to help with the aid operation, Reuters said.

International rescue teams began arriving with sniffer dogs and detection equipment. One dog team dug out 20 survivors, the official Islamic Republic News Agency said.

The use of dogs, which are considered unclean by most Muslims, was a sticking point in rescue efforts in 1990, after the most deadly earthquake ever to strike Iran. It killed about 50,000 people.

On Saturday, state television showed film of bloodied victims being loaded onto planes. A provincial official, Saeed Iranmanesh, told The Associated Press that more than 9,000 of the injured were sent to hospitals throughout the country.

The bodies of the dead lined streets. The International Red Crescent advised people in the city to wear gloves and face masks because of fears of an epidemic, Reuters reported.

There were burials, but they were swift and brutal. Broad trenches were dug with earthmoving equipment to accommodate hundreds of bodies at a time, The Associated Press reported. State television showed some bodies being stowed in the trunks of cars. Many more bodies were collected at cemeteries, the agency reported.

At another cemetery, The Associated Press said, workers prepared a mass grave as a cleric and 10 people prayed over a second.

At a news conference, the news agency reported, Mr. Lari, the interior minister, said: ''Bam has turned into a wasteland. Even if a few buildings are standing, you cannot trust to live in them.''

Indeed, aftershocks wrecked many buildings that had survived the initial quake. Witnesses said the last section of Imam Khomeini hospital that had remained standing collapsed on Saturday during an aftershock. Another hospital had also been destroyed.

About 600 prisoners escaped a ruined jail, local officials said, and other prisoners died in its wreckage, Reuters reported.

Refugees poured out of Bam on Saturday, according to Agence France-Presse, with the main road to Kerman jammed with thousands of cars packed with belongings. Tens of thousands of people, their homes destroyed, spent the night outside. With temperatures hovering around freezing overnight, some gathered around fires. Many continued to search the rubble for family members.

One woman cried and begged for help in front of her leveled house, according to a local journalist. The woman, Batul, 48, said her husband, 55, and three of her five children had died. Her daughter, 17, was badly injured but was among the relatively fortunate victims who received help at field hospitals. She had managed to find her husband's body, she said.

''I have lost everything, my home and my family,'' Batul said. ''We were all asleep when the earthquake happened and all I could do was to drag my 12-year-old son out of the house.''

State television showed an injured 5-year-old boy in a hospital in the city of Isfahan who said his mother and brother had been killed and his father taken to a hospital in Tehran.

A Kerman City official, Ali Karimi, said the historic quarter of Bam -- a mud city dating to the early years of the first century -- was destroyed.

Reports of injured and dead tourists began to filter in. The State Department said one American was killed and another seriously injured; the British Embassy in Tehran reported one British tourist missing.

Rescuers and equipment were arriving from around the world, and Iranian officials organized their deployment, dividing the city into six broad sections. Planes from China, Canada, Russia, Denmark, Britain, Belgium and Italy arrived on Saturday carrying rescuers, dogs, food and electronic search equipment, and more planes were expected. The United Nations said it was sending a planeload of equipment on Sunday.

Teams from about 20 countries were on the ground or about to arrive, Madeleine Moulin, a spokeswoman for the United Nations Office for the Coordination of Human Affairs, told Agence France-Presse.

The White House, which has had tense relations with Iran, announced on Saturday afternoon that it would send more than 200 civilian experts in urban search and rescue, emergency surgery and disaster response coordination.

The humanitarian delegation will include teams from Boston, Los Angeles and Fairfax County, Va., an administration statement said, along with disaster experts from the State Department and other agencies.

Pentagon teams will deliver more than 150,000 pounds of medical supplies from bases in Kuwait, the statement said, adding that the government is working with the Iranian authorities, the United Nations and the International Red Cross and Red Crescent to rapidly distribute the assistance.

The civilian teams will be flown to Iraq on Sunday by military transports, which will also carry food rations, blood, medicine, plastic sheeting, blankets and other supplies.

Throughout the country, people tried to find ways to help, too. State television showed Iranians crowding hospitals to donate blood. People flooded aid centers with canned food, blankets and clothes.

''I feel like my own children are buried under the rubble,'' said a crying woman in Tehran, who donated blankets and bottled water. ''I want to go to the city and help, sending stuff is not enough.''